Term
| What does the ON position on the APU selector do? |
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Definition
Opens APU fuel valve and inlet door
Arms APU bleed air isolation valve
Activates DC or two AC pumps |
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Term
| What does the OFF position on the APU selector do? |
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Definition
Closes APU bleed air isolation valve
Initiates normal shutdown
Resets auto shutdown fault logic (except for bleed leak) |
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Term
| When does the EICAS memo APU RUNNING display? |
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Definition
APU selector ON
N1 RPM > 95% |
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Term
| What APU information is provided on the APU Status page? |
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Definition
| EGT, N1, N2, oil quantity |
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Term
| What does RF or LO mean on the APU EICAS page? |
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Definition
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Term
| Where does the APU controller receive power? |
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Definition
Primary: APU battery
Standby: Main battery |
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Term
| What provides power to the APU starter? |
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Definition
When Utility Bus 4 is powered, DC electric starter through TR
or
24 volt APU battery |
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Term
| What APU components are powered by the APU and Main batteries? |
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Definition
APU:
Inlet door, APU controller, DC fuel pump, APU fire detection
Main: APU fire extinguisher, APU fuel valve, Stby power for APU controller |
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Term
| Which pumps operate the APU? Where are they located? |
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Definition
Two AC or one DC pump
Main Tank 2: DC pump and one AC pump
Main Tank 3: second AC pump |
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Term
| What are the APU start sequence limits when using the TR? |
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Definition
Between 1st and 2nd start: 1 min
2 - 3: 10 min
3 - 4: 75 min |
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Term
| What are the APU start sequence limits when using battery power? |
|
Definition
Between 1st and 2nd: 1 min
2 - 3: 1 min
3 - 4: 75 min |
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Term
| What happens if the TR overheats during APU start? |
|
Definition
Start power is transferred to the battery and the start continues on battery power
Any further TR start attempts are inhibited |
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Term
| How does a TR failure affect APU starting? |
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Definition
Does not automatically switch to APU battery
Switch Start Source to BATTERY
(except for overheat) |
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Term
| Describe the APU shutdown sequence |
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Definition
APU selector to OFF
Bleed air valve closes
60 second cool down
APU fuel valve closes
20% N1, Inlet door closes
After 2 min, shutdown is complete (fire detection capability) |
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Term
What causes an APU
auto-shutdown? |
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Definition
Limit is exceeded
Fire is detected
Battery switch turned OFF during shutdown sequence |
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Term
| What happens if the battery switch is placed to OFF prior to completion of the cool down period? |
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Definition
| APU shuts down immediately |
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Term
| How long do you wait before turning the battery switch OFF after the APU selector is OFF? Why? |
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Definition
2 minutes
Allows a complete shutdown sequence with fire detection capability |
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